As the demand for water has grown, industry has long sought processes for the desalination of salt water, such as seawater or brackish water. Some processes that have been used to desalinate water are distillation and membrane processes, such as reverse osmosis, nanofiltration, and electrodialysis.
Water recovery is a major economic parameter of drinking water production. However, this parameter is typically limited in existing processes. In addition to limited water recovery, another drawback is that these processes are typically considered energy intensive. Membrane based systems can suffer from additional problems. For example, membrane fouling and scaling in pressure-driven membrane processes (e.g., in reverse osmosis and nanofiltration) are often a major area of concern, as they can increase the cost of operating and maintaining the systems. Pretreatment of the feed water is a way of reducing fouling and scaling, but it can be complex due to variation in raw water quality, environmental impacts, and cost. An additional drawback of most membrane-based systems is that increased salt content of the feed stream typically reduces the flux of product water due to the high osmotic potential difference between the feed solution and the permeate.
Seawater desalination has become a common practice to supply the growing demand for water in areas having access to the sea. Shortage of potable (drinking) water in inland areas pose much more complicated challenges to water authorities, governments, and other stakeholders. Inland regions are typically restricted to the use of already overly allocated surface water and groundwater.
In addition, many desalination process are very sophisticated, costly, and energy intensive. These technologies may be infeasible for developing countries, which thus may lack sufficient access to safe drinking water supplies.